1. Field of the Invention
The present invention relates to a time-sharing control system and a method thereof, in particular to an electronic tag time-sharing control system and a method thereof.
2. Description of the Related Art
Zigbee (802.15.4) featuring the low power consumption and low cost has better advantages on industrial and household applications in the field of automatic controls than other wireless transmission technologies, therefore ZigBee is suitable for security, positioning, environment monitoring and healthcare.
For example, a wireless ZigBee network includes two communication standards established by different units. One of the communication standards is a standard introduced by the ZigBee Alliance that defines a network layer, a security layer and an application layer, and the other one is the 802.15.4 standard established by the Institute of Electrical and Electronics Engineers (IEEE) that defines a physical layer (PHY Layer) and a media access control layer (MAC layer).
Based on the IEEE 802.15.4 specification, the ZigBee Alliance defines a specification for a network layer, an application layer and a security layer, wherein the network layer is responsible for establishing and management a network mechanism, and has the functions of self-configuring and self-repairing a routing path. In the network layer, the ZigBee standard defines the functions of the aforementioned coordinator, router and end device. The coordinator is responsible for establishing personal area network formation (PAN formation) of the ZigBee wireless network, and the allocation of network addresses. The router is primarily responsible for searching, establishing, and restoring the routing path of data packets and responsible for transmitting the data packets. The end device can only select joining the formed ZigBee wireless network (PAN) and receive and transmit data, but cannot perform a routing of the packets.
Although ZigBee can save the power consumption substantially to extend the idling time of the end device by the aforementioned method, yet the practical application of ZigBee still has the following drawbacks:
1. If the quantity of end devices is huge, and all end device are standby simultaneously, the load of a coordinator and a router will be very heavy, and the bandwidth of a network will be insufficient for use, and the overall performance will be low. Packet collisions and use of some channels overlapped with WiFi, the problem of noise interference becomes increasingly greater as the quantity of end devices increases, and difficult to overcome.
2. Although the original design of ZigBee network architecture has taken the low power consumption into consideration, yet the end devices require a long idling time, and thus its power consumption is still high and the end devices fail to extend their ready-to work time.